Implement object pooling for CallStackElements

stagemonitor · Jul 16, 2015 · 15fe850 · 15fe850
1 parent 24ec2d2
commit 15fe850
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Showing 5 changed files with 69 additions and 19 deletions.
diff --git a/stagemonitor-requestmonitor/src/main/java/org/stagemonitor/requestmonitor/RequestTrace.java b/stagemonitor-requestmonitor/src/main/java/org/stagemonitor/requestmonitor/RequestTrace.java
@@ -1,5 +1,10 @@
 package org.stagemonitor.requestmonitor;
 
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.Date;
+import java.util.UUID;
+
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
@@ -11,11 +16,6 @@
 import org.stagemonitor.core.util.StringUtils;
 import org.stagemonitor.requestmonitor.profiler.CallStackElement;
 
-import java.io.PrintWriter;
-import java.io.StringWriter;
-import java.util.Date;
-import java.util.UUID;
-
 /**
  * A request trace is a data structure containing all the important information about a request.
  */
@@ -279,4 +279,9 @@ public interface GetNameCallback {
 		 */
 		String getName();
 	}
+
+	@Override
+	public void finalize() {
+		callStack.recycle();
+	}
 }
diff --git a/...questmonitor/src/main/java/org/stagemonitor/requestmonitor/profiler/CallStackElement.java b/...questmonitor/src/main/java/org/stagemonitor/requestmonitor/profiler/CallStackElement.java
@@ -1,10 +1,12 @@
 package org.stagemonitor.requestmonitor.profiler;
 
+import java.util.ArrayDeque;
 import java.util.Deque;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
+import java.util.Queue;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 
@@ -25,26 +27,51 @@ public class CallStackElement {
 	private long executionTime;
 	private List<CallStackElement> children = new LinkedList<CallStackElement>();
 
-	public CallStackElement(String signature) {
-		this(null, signature);
+	private static ThreadLocal<Queue<CallStackElement>> objectPool = new ThreadLocal<Queue<CallStackElement>>() {
+		@Override
+		protected Queue<CallStackElement> initialValue() {
+			return new LimitedQueue<CallStackElement>(10000);
+		}
+	};
+
+	public static CallStackElement createParent(String signature) {
+		return CallStackElement.create(null, signature, System.nanoTime());
 	}
 
-	public CallStackElement(CallStackElement parent, String signature) {
-		this(parent, signature, System.nanoTime());
+	public static CallStackElement create(CallStackElement parent, String signature) {
+		return CallStackElement.create(parent, signature, System.nanoTime());
 	}
 
 	/**
 	 * This static factory method also sets the parent-child relationships.
 	 * @param parent the parent
 	 * @param startTimestamp the timestamp at the beginning of the method
 	 */
-	public CallStackElement(CallStackElement parent, String signature, long startTimestamp) {
-		executionTime = startTimestamp;
-		this.signature = signature;
+	public static CallStackElement create(CallStackElement parent, String signature, long startTimestamp) {
+		final Queue<CallStackElement> pool = objectPool.get();
+		CallStackElement cse = pool.poll();
+		if (cse == null) {
+			cse = new CallStackElement();
+		}
+
+		cse.executionTime = startTimestamp;
+		cse.signature = signature;
 		if (parent != null) {
-			this.parent = parent;
-			parent.getChildren().add(this);
+			cse.parent = parent;
+			parent.getChildren().add(cse);
+		}
+		return cse;
+	}
+
+	public void recycle() {
+		parent = null;
+		signature = null;
+		executionTime = 0;
+		for (CallStackElement child : children) {
+			child.recycle();
 		}
+		children.clear();
+		objectPool.get().add(this);
 	}
 
 	public void removeCallsFasterThan(long thresholdNs) {
@@ -250,4 +277,19 @@ private boolean isLastChild() {
 	private boolean isRoot() {
 		return parent == null;
 	}
+
+	private static class LimitedQueue<T> extends ArrayDeque<T> {
+		private final int limit;
+
+		private LimitedQueue(int limit) {
+			super(limit);
+			this.limit = limit;
+		}
+
+		@Override
+		public boolean add(T t) {
+			return size() != limit && super.add(t);
+		}
+	}
+
 }
diff --git a/...nitor-requestmonitor/src/main/java/org/stagemonitor/requestmonitor/profiler/Profiler.java b/...nitor-requestmonitor/src/main/java/org/stagemonitor/requestmonitor/profiler/Profiler.java
@@ -15,7 +15,7 @@ private Profiler() {
 	public static void start(String signature) {
 		final CallStackElement parent = methodCallParent.get();
 		if (parent != null) {
-			methodCallParent.set(new CallStackElement(parent, signature));
+			methodCallParent.set(CallStackElement.create(parent, signature));
 		}
 	}
 
@@ -32,7 +32,7 @@ public static void addIOCall(String signature, long executionTimeNanos) {
 
 	public static void addCall(String signature, long executionTimeNanos) {
 		final CallStackElement currentCall = methodCallParent.get();
-		new CallStackElement(currentCall, signature, executionTimeNanos);
+		CallStackElement.create(currentCall, signature, executionTimeNanos);
 	}
 
 	public static boolean isProfilingActive() {
@@ -46,7 +46,7 @@ public static boolean isProfilingActive() {
 	 * @return the root of the call stack
 	 */
 	public static CallStackElement activateProfiling(String signature) {
-		CallStackElement root = new CallStackElement(signature);
+		CallStackElement root = CallStackElement.createParent(signature);
 		methodCallParent.set(root);
 		return root;
 	}

diff --git a/...tmonitor/src/test/java/org/stagemonitor/requestmonitor/profiler/CallStackElementTest.java b/...tmonitor/src/test/java/org/stagemonitor/requestmonitor/profiler/CallStackElementTest.java
@@ -15,13 +15,13 @@ public void printPercentAsBar() throws Exception {
 
 	@Test
 	public void testGetShortSignature() {
-		CallStackElement callStackElement = new CallStackElement("public void org.stagemonitor.requestmonitor.profiler.CallStackElementTest.testGetShortSignature()");
+		CallStackElement callStackElement = CallStackElement.createParent("public void org.stagemonitor.requestmonitor.profiler.CallStackElementTest.testGetShortSignature()");
 		Assert.assertEquals("CallStackElementTest#testGetShortSignature", callStackElement.getShortSignature());
 	}
 
 	@Test
 	public void testGetShortSignatureTotal() {
-		CallStackElement callStackElement = new CallStackElement("total");
+		CallStackElement callStackElement = CallStackElement.createParent("total");
 		Assert.assertNull(callStackElement.getShortSignature());
 	}
 }
diff --git a/...estmonitor/src/test/java/org/stagemonitor/requestmonitor/profiler/ManualProfilerTest.java b/...estmonitor/src/test/java/org/stagemonitor/requestmonitor/profiler/ManualProfilerTest.java
@@ -108,6 +108,7 @@ public void testProfiler() {
 						"000050.00  005% :--------- 000050.00  005% :---------         |-- select * from user \n" +
 						"000050.00  005% :--------- 000050.00  005% :---------         |-- select * from address \n" +
 						"000250.00  025% ||:------- 000250.00  025% ||:-------         `-- method1_2_1()\n", callStackElement.toString());
+		callStackElement.recycle();
 	}
 
 	@Test
@@ -129,6 +130,7 @@ public void testRemoveCallsFasterThan() {
 						"000050.00  005% :--------- 000050.00  005% :---------         |-- select * from user \n" +
 						"000050.00  005% :--------- 000050.00  005% :---------         |-- select * from address \n" +
 						"000250.00  025% ||:------- 000250.00  025% ||:-------         `-- method1_2_1()\n", callStackElement.toString());
+		callStackElement.recycle();
 	}
 
 	@Test
@@ -149,6 +151,7 @@ public void testRemoveCallsFasterThanNotIncluded() {
 						"000050.00  005% :--------- 000050.00  005% :---------         |-- select * from user \n" +
 						"000050.00  005% :--------- 000050.00  005% :---------         |-- select * from address \n" +
 						"000250.00  025% ||:------- 000250.00  025% ||:-------         `-- method1_2_1()\n", callStackElement.toString());
+		callStackElement.recycle();
 	}
 
 	@Test